1. Field of the Invention
The invention relates to an exchangeable oscillating pipette needle for an automatic analyzer for examining biological body fluids.
2. Description of the Related Art
It is known that in automatic analyzers which are used for examining biological body fluids, the required reagents are introduced into a measurement cell by means of an oscillating pipette needle. The pipette needle also has the role of ensuring that the body fluid to be examined is thoroughly mixed with the reagents. For this purpose, it is necessary for the pipette needle to be moved in oscillations. When introducing the reagents, and during the subsequent oscillations, there is a risk of the sensitive pipette needle colliding with the measurement cell or other apparatus parts, being damaged as a result, and having to be replaced because it is no longer fit for use. To date, exchanging the pipette needle has been associated with considerable technical effort, which can only be provided by a suitably trained service engineer. Not only do the pipette needle and other mechanical parts need to be exchanged, but also the motor and the means of heating the pipette needle. The associated lost time and the costs involved led to the need to develop a new construction for an oscillating pipette needle which allows the personnel operating the analyzer to exchange a damaged pipette needle quickly and in a straightforward way without having to call on the services of a specially trained engineer.
It is the object of the present invention to provide an oscillating pipette needle which is easily replaceable. This object is fulfilled by the present invention, an oscillating pipette needle for an automatic analyzer for examining biological body fluids, in which, for the purpose of introducing the pipette needle into the analyzer and withdrawing it from the analyzer, a holder 1 is provided which is equipped with a tension spring 3 and with which the oscillating arm, carrying the pipette needle 4 and resting on a knife-edge bearing, is fixed in a stationary position and is releasably connected.